Area Forecast Discussion
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FXUS61 KLWX 301529
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1029 AM EST Wed Nov 30 2016
Low pressure over the upper Great Lakes will track into eastern
Canada tonight. An associated cold front night will push through
the Mid Atlantic late tonight. High pressure will return to the
region Friday and Saturday. Low pressure will track to the west of the
region Sunday night. High pressure returns Monday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Have canceled the Dense Fog Advisory everywhere...visibilities
have gradually improved as showers (and warm front) continue to
lift northward. Though, there could still be some patchy dense
fog until warm front lifts north into PA over next few hours.
Warm air advection showers continue to move northward with the
warm front...with the most widespread activity remaining across
NE MD. Expect showers to continue to push northward through the
remainder of the morning as warm front lifts north into PA. This
should lead to a break in the rainfall (especially along/east of
I-95)...before the next round of rainfall moves through later
SPC currently has our area outlined in a marginal risk for
severe weather (due primarily to very high shear)...with the best
potential coming later this afternoon/evening as a thin line of
showers (and perhaps some embedded thunder) move through. This
might not be until after 6 PM for the DC/Balt metro. Though, best
chance for locally stronger wind gusts would be across southern
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
The longwave trough axis currently over the southern Great Plains
will reach the mid-Atlantic by sunrise Thursday. An associated cold
front will cross the area tonight, clearing out rain.
Gusty west wind up to 30 mph both Thursday and Friday with little
upslope snow. Maxima mid to upper 50s in dry air advection Thursday
and five or so degrees less Friday after continued cold air
.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure will reside over the east coast Saturday. With the
upper level flow in a zonal pattern temperatures will be right
around climo norms for the beginning of Dec - near 50. Radiational
cooling will allow temps to fall to around or slightly below the
freezing Saturday night.
Last night the models had some differences regarding the Sunday
forecast but these seem in better line today. An open short wave
is expected to track to our NW while high pressure moves into the
Atlantic. There`ll be a chance of rain during the afternoon in the
central Shenandoah Valley..with the moisture tracking north Sunday
night. We are presently forecasting mixed precipitation west of
I-95...but confidence is low with regard to the frozen precip.
The high moving away means that cold air will not be held to our
north which is essential..especially in a marginal situation like
this. Lows expected to be in the lower to mid 30s.
High pressure returns for Monday. Highs near 50. Monday night lows
in the lower 30s.
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
Visibilities have gradually improved at all sites as clouds and
rain have spread northeast across the area. IFR conds expected to
prevail by afternoon due to low cigs. Additionally, some risk for
gusty showers later this afternoon/evening. Isolated thunder risk
this afternoon and evening, particularly southeast of DC. South
winds increase by midday with gusts into the 20 kt range.
Cold front crosses the area after midnight tonight with a shift to
west winds. Gusts in 25 kt range Friday and Saturday with VFR conds.
VFR conditions Saturday into the at least the first part of
Sunday. Clouds are expected to increase Sunday night with a chance
Just like yesterday, south winds increase today. Gusty showers
and isolated thunderstorms may trigger special marine warnings,
particularly in this afternoon/evening.
A cold front crosses the area tonight with a shift to west winds
after midnight. West winds mix down through Thursday with gusts
around 25 knots across the waters. SCA through Thursday for now and
is likely again both Friday and Saturday.
SCA level wind gusts possible Saturday. No problems foreseen
Southerly flow continues on the water today ahead of a cold front
that will cross late tonight. Winds will generally be 15 knots
gusting 20 knots which would not cause much of a surge and the
forecast is for water levels to remain below action stage thresholds
for the preferred high tide this afternoon and evening. However,
stronger winds may mix down as showers and isolated thunderstorms
cross this afternoon. A stronger surge could occur with this
activity, perhaps raising levels somewhat. New moon is today.
MARINE...Small Craft Advisory until 6 PM EST Thursday for ANZ530>543.